Energy Recovery VentilatorMarvair’s high efficiency wall mount heat pumps and air conditioners are available with the GreenCube Energy Recovery Ventilator. The GreenCube ERV is an enthalpy plate energy exchanger with no moving parts that recovers both sensible and latent energies from one air stream and transfers it to another in a cross flow arrangement. The GreenCube ERV is certified in accordance with ARI standard 1060-2005.